A and B can do a piece of work in 6 and 12 days, respectively. They (both) will complete the work in how many days?
Correct Answer: 4 days
Explanation:
A's 1 day's work = 1/6
B's 1 day's work = 1/12
(A + B)'s 1 day's work = 1/6 + 1/12
= (2 + 1)/12 = 3/12 = 1/4
Hence, both will complete the work in 4 days.
